Automatic reciprocator with manifold and sleeve valve

Abstract

A pneumatic reciprocator includes a cylindrical air cylinder concentrically mounted within a cylindrical manifold. A cylindrical sleeve valve is concentrically mounted for movement along the manifold by a pair of spaced O rings. Two sets of circumferentially arranged air holes in the manifold are alternately covered and uncovered by the O rings as the sleeve valve is moved to selectively pressurize and vent opposite sides of the piston in the air cylinder. Movement of the sleeve valve is controlled by stops on the movable bed of a surface grinder that is controlled by the air cylinder.

What is claimed is: 
     
       1. A pneumatic reciprocator comprising: an air cylinder including a movable piston assembly and air passageways;   manifold means substantially surrounding said air cylinder and isolating said air passageways; and   sleeve valve means movably mounted on said manifold means for supplying compressed air to said air passageways in accordance with the position of said sleeve valve means on said manifold means.   
     
     
       2. The reciprocator of claim 1 wherein said movable sleeve valve means and said manifold means are cylindrical in shape and are concentrically positioned with respect to each other by a pair of resilient annular seals. 
     
     
       3. The reciprocator of claim 2, further including two sets of circumferentially arranged air holes in said manifold means cooperating with said resilient annular seals for pressurizing one side of said piston assembly and venting the opposite side of said piston assembly. 
     
     
       4. The reciprocator of claim 3 wherein said cylindrical sleeve valve means includes an undercut portion between said pair of resilient annular seals for increasing the volume of compressed air available to said air holes in said manifold means. 
     
     
       5. The reciprocator of claim 4 wherein said pair of resilient annular seals are spaced apart by a distance that is greater than the distance between said sets of circumferentially arranged air holes. 
     
     
       6. The reciprocator of claim 5, further comprising boot means, including vent means, coupled between said sleeve valve means and said manifold means, said boot means always being under positive pressure. 
     
     
       7. A pneumatic reciprocator comprising: a cylindrical air cylinder including a movable piston assembly and air passageways;   cylindrical manifold means substantially surrounding said air cylinder and isolating said air passageways;   cylindrical sleeve valve means including spaced apart resilient annular seal means engaging said manifold means, said sleeve valve means being movable back and forth along said manifold means for supplying compressed air to said air cylinder via said air passageways; and   two sets of circumferentially arranged and spaced apart air holes in said manifold means in respective communication with said air passageways.   
     
     
       8. The reciprocator of claim 7 wherein the distance between said resilient annular seals is greater than the distance between said two sets of air holes. 
     
     
       9. The reciprocator of claim 8 wherein said resilient annular seals are "O" rings of high durometer and wherein said holes are sufficiently small to minimize extrusion into said air holes. 
     
     
       10. The reciprocator of claim 9 wherein the distance between said "O" rings is approximately three inches. 
     
     
       11. The reciprocator of claim 10, further comprising boot means, including vent means, coupled between said sleeve valve means and said manifold means, said boot means always being under positive pressure.